Method and mechanism for feeding of wires, wire rods, tubes or other material of prismatic cross section from different feeding lines to one processing line

ABSTRACT

The present invention refers to a method and a mechanism for convergence of a multitude of wires (1-4) wire rods, tubes, or other material of prismatic cross section to one particular line (OO′), where the material may be cut and stored or may be cut and bent or may be cut and welded or may be cut and processed in another way. The method depends on the elastic properties of metals, which can be temporarily deformed when under stress, and are restored to their original shape when the stress load is removed, as long as the stressing of the metal remains in the elastic region. Hence, during the convergence of wires, there is a minimum distance between the feeding-straightening (6-9) units and the point of convergence to a common line, which is defined by the material with the weakest elastic properties and by the locations of the feeding lines. The method can be applied to feeding lines, which are parallel with each other or not, and for feeding lines, which lie or not on the same plane.

This Application is a Continuation of copending U.S. application Ser. No. 10/493,024 filed under 35 U.S.C. sec. 371 Apr. 19, 2004 (status now ______) as a U.S. national-phase entry of PCT International Application No. PCT/GR03/00005 filed on Feb. 5, 2003; which claimed foreign priority of Greek national Application No. GR200201 00114 filed on Feb. 28, 2002. The entirety of parent U.S. application Ser. No. 10/493,024 and the entirety of parent PCT International Application No. PCT/GR03/00005 are hereby incorporated herein by reference.

The present invention refers to a method and a mechanism for selection and feeding of one at a time, from a bundle of several wires or wire rods or tubes or other materials of prismatic cross section, which are placed on different feeding lines, where these lines may or may not be parallel to each other in space, and they may or may not lie on the same plane. The location of processing, where the feeding lines converge at, may be fixed with respect to the feeding lines or may be able to move at a direction parallel to its axis or may be able to even turn its axis at an angle with respect to the initial axis in order to facilitate the operation of the mechanism.

Selection of each wire to be fed is conducted without the employment of any special mechanisms, in a very simple way, which is explained below.

The method and the mechanism are applied to straightening machines, where several, usually parallel with each other, wires or wire rods are pulled from pay-off stations, are straightened in the respective straightening units, and consequently, one of them is selected for advancement to a cutting, storage and transfer mechanism.

The present invention is also applied to bending machines, where several wires of different cross section are fed at, and one of them is selected for straightening and feeding towards the bending mechanisms.

The present invention can also be applied to welding machines, which are used for the production of different mesh geometries, where the distance between the longitudinal wires varies.

The usual practice consists of placing the straightening units on a plate, which can move on its plane, in a direction transversal to the parallel wires, so that one straightening wire line is always placed along the cutting and storage axis of the already straightened wires or along the axis of any consecutive processing. Whenever a change of wire is required, the plate moves at the transversal direction and the selected wire is aligned to the axis of cutting or storage or of any consecutive processing step.

Alternatively, the straightening units are placed on a mechanism, which is able to rotate about an axis, so that the selected straightening unit is aligned with the axis of cutting or of any consecutive processing step.

The main disadvantage of both the above methods and applications is the complexity and the size of the mechanical construction and the significant time, which is required for the changing of wire.

The mass of the plate, which supports the straightening units is significant, hence its structure much be robust and a complex, therefore expensive, mechanism is required for the plate movement. Furthermore, in the case of wire changing, additional time is required for the plate movement, so that the selected wire line be aligned with the axis of any further processing step, and consequently, the productivity of the machine is reduced.

The purpose of the present invention is to present a method, which will resolve any problems of the existing methods and machines and which will lead to the manufacturing of a mechanism, which will make possible the fast interchanging of production lines, simply and quickly.

The aim of the present invention is to supply a mechanism, which will automate the process of interchanging of the production lines, will maximize flexible operation, will minimize the time required for the changing of production lines, and as a mechanism, it will be simple in its design, user-friendly and reliable in operation.

The method of the present invention is based on the elasto-plastic behavior of metals, when they undergo bending. In FIG. 1, wire (1) advances along the axis AA′ towards the straightening unit (6), where it undergoes straightening, and then the straightened wire is guided, so that it is aligned to the axis 00′ after an interval X, where the wire is bent and is finally taking an S shape. For materials which express an elasto-plastic behavior, such as metal wires, wire rods, metal tubes and generally the materials of prismatic cross section, for a certain S shape, there exists an adequate convergence distance X where the material remains in the elastic region and it does not exhibit any permanent deformation.

More specifically, there is a relation between the geometry of the S-curve, the transversal distance Ψ, the wire diameter, the convergence length X, and the material yield point, so that no plastic deformation of the wire occurs.

According to the method of the present invention, the axis AA′ of the wire feeding can be maintained fixed with respect to the axis OO′ of the collection mechanism. In addition, the axis of feeding of the wire can move with respect to the axis OO′ of the collection mechanism or the axis OO′ of the collection mechanism can move with respect to the axis AA′ of the wire feeding. Furthermore, the two axes can change the angle of convergence between them. Prerequisite of all the above changes is that no plastic deformation of the fed material occurs.

According to the method, FIG. 2, the feeding wires (1), (2) etc. and the straightening units (6), (7) etc., are placed on parallel axes and at adequate distances between them. The common cutting location (23) and the beginning of various mechanisms, e.g. bending devices or transport mechanism towards the bending devices, are aligned with axis OO′. The distance X between the common cutting location and the locations where the wires exit from the straightening units is selected to be sufficiently long, so that none of the converging wires is plastically deformed

The minimum X distance is defined for the worst case, so that all the wires may arrive at the common convergence location, without any plastic deformation.

During operation, only one wire is fed at each time.

The straightening units may be placed on the same plane and parallel to each other, at various relative to each other locations, FIG. 3, whereas their convergence may begin at different locations, so that a variety of manufacturing goals are achieved, such as minimum distances between straightening units.

The straightening units may also be placed not on the same plane but may lie on different planes, FIG. 4. However, the wires must converge towards the convergence location without any plastic (permanent) deformation.

The wire lines may lie on the same plane but not parallel to each other, being placed at an angle with respect to the common convergence line.

In addition, the axes of the wire lines may be not lie on the same plane in space, as soon as they converge towards the common axis OO′, through the appropriate s-shaped curves.

Furthermore, the axis OO′ may move at a direction parallel to itself, FIG. 2 (y), or at an angle, FIG. 2 (φ), with respect to the lines of feeding of the wires, as soon as the fed material does not undergo any plastic deformation.

More details about the method and machine according to the present invention will be better understood during the description of the particular implementation, which follows. The machine is described in the attached drawings, in the sense of a non-restrictive example and without limitation in the range of the applications of the method.

FIG. 1—The principle of the present method is presented for one wire.

FIG. 2—The method is presented in a 4-wire example.

FIG. 3—The method is presented in the example of the minimum distances from the axis of convergence.

FIG. 4—The example of wires being spatially distributed is presented.

FIG. 5—One implementation of the present method is presented, where all the wires extend up to the cutter.

FIG. 6—The mechanism cutter for the implementation of FIG. 5 is presented.

FIG. 7—A second implementation is presented, where only one wire reaches the cutter at a time.

FIG. 8—The cutter of the mechanism of the implementation of FIG. 7 is presented.

An implementation of the present method is presented in FIG. 5. After its exit from the straightening unit (6), the wire (1) is guided towards rollers (11) for the measuring of length, and then towards the cutter (23), through a guiding tube (18). The tube (18) is bent in such a fashion, that the wire passing through it to exit without any permanent deformation. The above tubes (18) are mounted on the body of the machine.

In the same manner, the remaining wires are guided from the straightening units to the machine common cutter.

One straightening unit operates each time on these machines hence only one wire is fed at each time. The length of the wire feeding is measured through a mechanism with rollers (11), (12), (13), (14), by a pulse generator (15). The length of the wires, which are cut by the cutter, is determined by taking into account the length of the wires in the tube.

In the particular implementation the cutter (23), FIG. 6, is characterised by a fixed cutting tool (24) with openings (holes) corresponding to the wires, and by a moving 5 cutting tool (32), which can move at a sufficient distance, in order to cut through all the wires which have been fed. In case only one wire is fed at each time, the moving cutting tool cuts through only the particular wire.

With respect to the mechanism operation, a wire is fed at each time step, it is being straightened, measured, and then it is cut and formed in the mechanisms that follow. The wire selection is implemented upon activation of the motor of the respective straightening unit.

Alternatively, the method is implemented with the mechanism of FIG. 7, which is characterised by a cutter (30) with a fixed cutting tool (31) with an opening (hole) corresponding to wires of the largest diameter, and with a pair of measuring rollers (29) and a pulse generator just before the cutter. As an example, the wire (1 ) is fed to the straightening unit (6) and then, through the tube (1 8), it converges towards the cutter (30). In the vicinity of the cutter (30), the wires are transferred through guides of appropriate number and shape, which are shown in FIG. 7 as parts (25), (26) and (27), and afterwards only one wire at each time is transferred to the cutter (30) through a guide (28) and the measuring rollers (29). The cutter (30) consists of a fixed cutting tool (31 ) with openings that allow the transfer of wires of the smallest as well as the largest diameters, whereas the moving cutting tool (32) can travel a sufficient distance in order to cut wires of any diameter.

Operation of the straightening units can depend on the use of plain rollers, of rotor with rollers, of rotor with bushes etc. and is not related to the proposed patent of the convergence mechanism.

Straightening units may not even exist, as in the case of already straightened and cut metal bars, which are only fed to the convergence mechanism.

The convergence of the wires may be forced by passing of the wires through tubes, which are adequately curved. Convergence can also take place by passing of the 

1. A method for the selection of a feeding wire or wire rod or tube or other material of prismatic cross section from more than one feeding and straightening lines, and guidance along a particular axis OO′ for further processing, where the method is characterised by the advancement of the selected wire towards axis OO′ while at the same time it is deflected from its original alignment, following an appropriate curved path, where no permanent plastic deformation of the wire occurs.
 2. A method according to claim 1, which is characterised by the selection and feeding of only one wire from several feeding and straightening lines, which may lie on the same plane, and may or may not be parallel to each other.
 3. A method according to claim 1, which is characterised by the selection and feeding of only one wire from several feeding and straightening lines, which may or may not be parallel with each other in space.
 4. A method according to claim 1, which is characterised by a collection and transfer line, which may be fixed with respect to the feeding lines or it may move in a sense parallel to itself or it may even rotate at an angle with respect to its original alignment.
 5. A machine for the selection of a feeding wire or wire rod or tube or other material of prismatic cross section from more than one feeding and straightening lines, and guidance along a particular axis OO′ for further processing, where the method is characterised by the guidance of the wires (1 ) etc. through the straightening units (6) etc. with guides (1 8) etc., which are arranged in such a manner on an appropriate curve, that no plastic deformation of the wires occur, where the wires are guided towards a common for all wires cutter (23) and then towards the next processing step on axis OO′ , and where the advancement of the fed wire is measured by a length-measuring device.
 6. A machine according to claim 5, which is characterised by the measuring of the length of the advancement of the fed wire by measuring rollers (11 ) etc., located before the convergence mechanism, and by the converge of all the wires to the cutter (23), which is characterised by a fixed cutting tool (24) with as many openings as the fed wires, but where only one wire goes though the cutter (23) at each time, where it is cut after advancing at the appropriate distance.
 7. A machine according to claim 5, which is characterised by the measuring of the length of the wire advancement by measuring rollers (29) after the convergence of the wires and before the location of the cutter (30), where only one wire reaches the measuring rollers and the cutter, where it is consequently cut after been fed at the appropriate length. 